import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;

public class PangramChecker {

    final String pangram = "The quick brown fox jumps over the lazy dog";

    public boolean isPangram(String input) {
        if (null == input || input.isEmpty()) {
            return false;
        }

        Pattern r = Pattern.compile("[a-z]");

        String lowerInput = input.toLowerCase();
        Matcher m = r.matcher(lowerInput);
        char[] m2 = new char[26];
        while(m.find()){
            char c = m.group().toCharArray()[0];
            m2[c-'a'] += 1;
        }

        for (int i = 0; i < m2.length; i++) {
            if (m2[i] == 0){
                return false;
            }
        }

        return true;
    }

}
